1. The Field of the Invention
This application relates generally to noise reducing devices. In particular, this application discusses noise reducing devices for use with pneumatically operated tools, such as pneumatic percussive drills.
2. The Relevant Technology
The process of converting energy stored in compressed air into motion for powering a pneumatic tool generates a significant amount of noise as the spent air (exhaust) is exhausted. In particular, pneumatic tools are operated by compressed air that enters a sealed chamber, exerts pressure on an internal piston, and causes the piston to move forward and back repeatedly. As spent compressed air is exhausted from the sealed chamber, the compressed air expands rapidly causing a loud noise. Often, the operation of pneumatic tools requires a close proximity between the tool and an operator, and the noise generated by the tool can be loud enough to be potentially harmful the operator.
There are many approaches to reduce the noise from these devices. A common approach is a muffler consisting of an expansion chamber into which the exhaust flows and expands before venting to the atmosphere. Such designs take various geometric shapes including cylindrical, kidney-shaped, and rectangular. Another approach includes incorporating a series of internal chambers within an expansion chamber to allow the exhaust to progressively expand. The series of internal chambers can be made of metal alloys, polymers, composite, elastomeric, or foamed sound-absorbing materials.
While such approaches offer some improvement in noise reduction, they may be very complex and include several intricate parts that must be manufactured and fitted together at a significant cost. Many approaches use bulky devices that can obstruct the mobility and operation of the pneumatic tools with which they are used. Other approaches can restrict air flow and, thereby, result in reduced performance of the pneumatic tool. Additionally, given the close proximity of pneumatic tools and their operators, the noise reduction of current approaches is often insufficient to acceptably reduce the damaging and/or painful noise levels.
The subject matter claimed herein is not limited to embodiments that solve any disadvantages or that operate only in environments such as those described above. Rather, this background is only provided to illustrate one exemplary technology area where some examples described herein may be practiced